diff options
Diffstat (limited to 'gcc/gimple-fold.c')
| -rw-r--r-- | gcc/gimple-fold.c | 75 |
1 files changed, 61 insertions, 14 deletions
diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c index 36a85c7..e873320 100644 --- a/gcc/gimple-fold.c +++ b/gcc/gimple-fold.c @@ -1280,12 +1280,13 @@ gimple_fold_builtin_memset (gimple_stmt_iterator *gsi, tree c, tree len) obtained from the upper bound of an array at the end of a struct. Such an array may hold a string that's longer than its upper bound due to it being used as a poor-man's flexible array member. + Pass NONSTR through to children. ELTSIZE is 1 for normal single byte character strings, and 2 or 4 for wide characer strings. ELTSIZE is by default 1. */ static bool get_range_strlen (tree arg, tree length[2], bitmap *visited, int type, - int fuzzy, bool *flexp, unsigned eltsize = 1) + int fuzzy, bool *flexp, unsigned eltsize, tree *nonstr) { tree var, val = NULL_TREE; gimple *def_stmt; @@ -1307,7 +1308,8 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type, if (TREE_CODE (aop0) == INDIRECT_REF && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME) return get_range_strlen (TREE_OPERAND (aop0, 0), length, - visited, type, fuzzy, flexp, eltsize); + visited, type, fuzzy, flexp, + eltsize, nonstr); } else if (TREE_CODE (TREE_OPERAND (op, 0)) == COMPONENT_REF && fuzzy) { @@ -1335,13 +1337,14 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type, return false; } else - val = c_strlen (arg, 1, NULL, eltsize); + val = c_strlen (arg, 1, nonstr, eltsize); if (!val && fuzzy) { if (TREE_CODE (arg) == ADDR_EXPR) return get_range_strlen (TREE_OPERAND (arg, 0), length, - visited, type, fuzzy, flexp, eltsize); + visited, type, fuzzy, flexp, + eltsize, nonstr); if (TREE_CODE (arg) == ARRAY_REF) { @@ -1484,7 +1487,7 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type, { tree rhs = gimple_assign_rhs1 (def_stmt); return get_range_strlen (rhs, length, visited, type, fuzzy, flexp, - eltsize); + eltsize, nonstr); } else if (gimple_assign_rhs_code (def_stmt) == COND_EXPR) { @@ -1493,7 +1496,7 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type, for (unsigned int i = 0; i < 2; i++) if (!get_range_strlen (ops[i], length, visited, type, fuzzy, - flexp, eltsize)) + flexp, eltsize, nonstr)) { if (fuzzy == 2) *maxlen = build_all_ones_cst (size_type_node); @@ -1521,7 +1524,7 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type, continue; if (!get_range_strlen (arg, length, visited, type, fuzzy, flexp, - eltsize)) + eltsize, nonstr)) { if (fuzzy == 2) *maxlen = build_all_ones_cst (size_type_node); @@ -1554,21 +1557,30 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type, if we can determine string length minimum and maximum; it will use the minimum from the ones where it can be determined. STRICT false should be only used for warning code. + When non-null, clear *NONSTR if ARG refers to a constant array + that is known not be nul-terminated. Otherwise set it to + the declaration of the constant non-terminated array. ELTSIZE is 1 for normal single byte character strings, and 2 or 4 for wide characer strings. ELTSIZE is by default 1. */ bool -get_range_strlen (tree arg, tree minmaxlen[2], unsigned eltsize, bool strict) +get_range_strlen (tree arg, tree minmaxlen[2], unsigned eltsize, + bool strict, tree *nonstr /* = NULL */) { bitmap visited = NULL; minmaxlen[0] = NULL_TREE; minmaxlen[1] = NULL_TREE; + tree nonstrbuf; + if (!nonstr) + nonstr = &nonstrbuf; + *nonstr = NULL_TREE; + bool flexarray = false; if (!get_range_strlen (arg, minmaxlen, &visited, 1, strict ? 1 : 2, - &flexarray, eltsize)) + &flexarray, eltsize, nonstr)) { minmaxlen[0] = NULL_TREE; minmaxlen[1] = NULL_TREE; @@ -1580,19 +1592,39 @@ get_range_strlen (tree arg, tree minmaxlen[2], unsigned eltsize, bool strict) return flexarray; } +/* Return the maximum string length for ARG, counting by TYPE + (1, 2 or 4 for normal or wide chars). NONSTR indicates + if the caller is prepared to handle unterminated strings. + + If an unterminated string is discovered and our caller handles + unterminated strings, then bubble up the offending DECL and + return the maximum size. Otherwise return NULL. */ + tree -get_maxval_strlen (tree arg, int type) +get_maxval_strlen (tree arg, int type, tree *nonstr /* = NULL */) { bitmap visited = NULL; tree len[2] = { NULL_TREE, NULL_TREE }; bool dummy; - if (!get_range_strlen (arg, len, &visited, type, 0, &dummy)) + /* Set to non-null if ARG refers to an untermianted array. */ + tree mynonstr = NULL_TREE; + if (!get_range_strlen (arg, len, &visited, type, 0, &dummy, 1, &mynonstr)) len[1] = NULL_TREE; if (visited) BITMAP_FREE (visited); - return len[1]; + if (nonstr) + { + /* For callers prepared to handle unterminated arrays set + *NONSTR to point to the declaration of the array and return + the maximum length/size. */ + *nonstr = mynonstr; + return len[1]; + } + + /* Fail if the constant array isn't nul-terminated. */ + return mynonstr ? NULL_TREE : len[1]; } @@ -1635,7 +1667,19 @@ gimple_fold_builtin_strcpy (gimple_stmt_iterator *gsi, if (!fn) return false; - tree len = get_maxval_strlen (src, 0); + /* Set to non-null if ARG refers to an unterminated array. */ + tree nonstr = NULL; + tree len = get_maxval_strlen (src, 0, &nonstr); + + if (nonstr) + { + /* Avoid folding calls with unterminated arrays. */ + if (!gimple_no_warning_p (stmt)) + warn_string_no_nul (loc, "strcpy", src, nonstr); + gimple_set_no_warning (stmt, true); + return false; + } + if (!len) return false; @@ -3506,12 +3550,15 @@ static bool gimple_fold_builtin_strlen (gimple_stmt_iterator *gsi) { gimple *stmt = gsi_stmt (*gsi); + tree arg = gimple_call_arg (stmt, 0); wide_int minlen; wide_int maxlen; + /* Set to non-null if ARG refers to an unterminated array. */ + tree nonstr; tree lenrange[2]; - if (!get_range_strlen (gimple_call_arg (stmt, 0), lenrange, 1, true) + if (!get_range_strlen (arg, lenrange, 1, true, &nonstr) && lenrange[0] && TREE_CODE (lenrange[0]) == INTEGER_CST && lenrange[1] && TREE_CODE (lenrange[1]) == INTEGER_CST) { |